The present invention relates generally to a leak and defect testing device for containers, and more particularly to a continuously operating device that tests for leaks and defects in containers.
When containers are manufactured, especially blow-molded plastic containers, it is of great importance to be able to test the containers for leaks and defects before they are put into use. Such defects may include but are not limited to pin holes, malformed necks and neck obstructions that could inhibit filling.
A number of devices for testing container defects are known. As containers are conveyed along or through one of these prior devices, they may be “handled” using various methods, e.g. by using holding tools that maintain each container in a stationary position during testing, or by continuously stopping the conveyor so that each container may be tested. Freshly blow-molded containers may be hot and tacky. Contact with the container is in this state is undesirable as it can mar the fresh surface of the container and may cause containers to tip over and or jam the conveyor. Thus, time and product is wasted if even a single container becomes out of line.
Examples of prior art devices include U.S. Pat. No. 5,591,899 to Griesbeck. The patent discloses a device that in part, tests defects in containers using pressure and optoelectric means. Generally, a container is gripped at its necked surface and a sealing disk is pressed onto the container opening. A light or radiation source shines a radiation beam through the container to a receiver. The combination optic and pressure test will determine leakage and contamination defects. Greisbeck, however, requires that the containers be stabilized upon a carousel platform for testing which makes container handling more demanding and expensive. Further, the device cannot be easily used with an existing conveyor.
There is, thus, a demand for a simple and easily adjustable device for testing containers on an existing conveyor system, especially plastic bottles. It is especially desirable to be able to test such containers as to leakages and defects in one single step without contacting the container sides. It is also desirable to have a device that can maintain operation if a bottle tips over on the conveyor system.